Electrical connector systems are used for joining electrical circuits, wherein typically a male contact terminal is mated with a female contact terminal. In many applications a safe and particularly reliable coupling of contact terminals is of high importance. Especially in motor vehicles, where multiple electrically driven Supplemental Restraint Systems, commonly referred to as airbag systems, are needed to ensure an optimal interplay of safety components (e.g. between the airbag and the pre-tensioner of the safety belt) in an event of an accident.
US Patent Application Publication US 2004/0166715 A1 describes a typical squib connector arrangement as it is used in airbag systems. The squib contains explosive material that is detonated upon receipt of an electrical signal to cause the rapid release of high pressure gas to inflate the airbag. The arrangement comprises typically a socket assigned to the squib and a plug connector. The socket comprises two male terminals, namely pins, which come in electrical contact with the female terminals of the plug connector, when the same is plugged into the socket. In the arrangement disclosed in US '715 also a shorting clip is assigned to the socket, which is biased into electrical contact with the two pins to reduce the risk of misfiring by static electricity, for example during disassembly. The plug connector urges the shorting clip out of the electrical contact with the pins, when the plug connector is plugged into the socket. The connector further comprises a housing with a latch beam that is deflectable between a latched state and an unlatched state and a CPA (Connector Position Assurance) member mounted to the housing is movable between open and closed positions to provide a secondary lock and a visual verification of the correctly mated state.
As can be seen in FIG. 3 of US '715, cavities are provided in the housing. They are usually produced such that they follow the shape of uniform cylinders, with the purpose to house the female terminal leads, which have the task to establish a connection with the male terminals (pins).
These female terminals are usually produced from an “endless” plain strand of conductive material, e.g. metal. During terminal production, the strand is pierced and bend to its final shape and finally cut into smaller pieces to achieve the desired single terminal units. The terminals are usually bend in a way, that they comprise an upper portion having a cylindrical shape with a circular cross section. Also they are provided with springs, which are able to grab the male terminals and thus establish an electrical connection. A front view of such a terminal is depicted in FIG. 12 of US '715. The cylindrical part of the terminal is housed inside a corresponding cavity. For the simplification of production of the housing and to facilitate the assembly, cavities usually follow the cross sectional shape of the terminal, so that the terminals are able to fit tightly into the cavities.
The fixation of a terminal inside a cavity is usually caused by friction between the cylindrical shaped upper portion of the terminal (compare FIG. 11 of US '715) and the inner walls of the cavity. The abovementioned springs usually do not contribute to the fixation of the terminal since they need to be flexibly bendable in- and outwards so that they can grab the male terminals. Hence, quality of fixation is dependent on the upper part, more specifically on the frictional force between the inner walls of the cavity and the outer surface of the terminal cylinder.
This force can be increased for example by an increase in length of the cylindrical shaped part of the terminal, which is in contact with the inner walls of the cavity. When this so called “guiding length” is increased, fixation of the terminal inside the cavity is increased. A proper fixation of the terminal in turn ensures a proper guiding of the male pins into the female terminal during the mating process. If this proper fixation is not given, the terminal could possibly move to a certain degree inside the cavity, resulting in a non-proper established connection. Movement of the terminals can also be caused by pulling the cable that is connected to the connector. The shorter the “guiding length” is and the longer the spring arms are, the larger is the resulting lever effect, causing an alteration of the position of the contact point, where the male pin contacts the female terminal.
The design of such connectors is highly dependent on the desired place of installation. In motor vehicles, the connectors are widely used in supplemental restraint systems, like for example in airbag systems. Especially the installation of the electrical parts in certain armatures, for example in the steering wheel, is highly space constrained, so all parts have to be designed as less space consuming as possible.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.